Your Family Health History

A DNA Day Activity

The Pedigree

A pedigree is a drawing of a family tree The pedigree is used by genetic counselors and other medical professionals to assess families and try to spot patterns or indications which may be helpful in diagnosing or managing an individual’s healthPedigree uses specific symbols and “rules” so no matter who draws it, anyone can read and understand it

EXAMPLE

Pedigree from the National Society of Genetic Counselors website:www.nsgc.org

Creating Your Pedigree: 3 Steps

First step: talk to your family!Ask questions, write down what they say, collect all information possible

Draw a basic outline of your family tree using pedigree symbolsRecord the information you gathered on the drawing to complete the pedigree

Step 1: Your Family’s Information

Gathering Information

Write a list of all your family members, including:

Parents Brothers and sisters (include half-siblings)ChildrenGrandparentsAunts and unclesCousinsNieces and nephews

DON’T FORGET YOURSELF!

Gathering Information

Next to each family member’s name, write down everything you know about their health and medical historyIf you can later, ask family members questions and find out as much information as possibleInformation about health is a sensitive topic, so if you do talk to family members, make sure to be respectful of thisIf you are adopted, you can collect information on either or both your adopted and birth families

A pedigree of your adopted family will not give you much information about your own genetic make-up, but would tell you a lot about the family you are part of.A pedigree of your birth family will tell you more about your personal genetic history, but it may be more difficult to learn details

Information to Include

Age or date of birth (or best guess, e.g. 40’s)Date of death for family members who have passed away Height and weight (optional)For those with medical problems, write down things like if they smoked, diet or exercise habits, etc.For those with medical conditions, write down how old the person was when they were diagnosedWhere each side of your family comes from originally (e.g. England, Mexico, India, etc.)

Medical conditions such as:CancerHeart diseaseDiabetesAsthmaMental illnessHigh blood pressureStrokeKidney diseaseBirth defects (e.g. spina bifida, cleft lip, heart defect)Learning problems or mental retardationVision or hearing loss at a young ageKnown genetic conditions, like cystic fibrosis or sickle cell disease

Step 2: Drawing Your Family Tree

Symbols Used in Drawing

Male

Female

Gender unknown

A diagonal line through a symbol means a person is deceased

Brackets around a symbol and a dashed line leading to it means a person is adopted

P P PP stands for pregnancy – mother carrying a male, female, or unknown gender

Non-identical twins

Identical twins

3

To save space, you can sometimes write a number inside a symbol instead of drawing each symbol (e.g. three sisters)

Pregnancy loss (i.e. miscarriage, stillbirth, elective abortion)

Ready to Draw!

First, start with yourself!Place yourself towards the bottom or middle of the center of thepage, because older generations will go above youBut leave space underneath your symbol for your information

Date of birth, any medical conditions, height and weight (optional)

Squares represent males Circles represent females

An arrow next to you represents that YOU are the person who called attention to this family

Jane Jones b. 4/25/1990

asthma

Siblings

Draw your brothers and sisters next to yourselfOlder siblings go on your left, younger siblings on your rightThen draw vertical lines up from each sibling and connect the vertical lines with a horizontal line. This represents a sibship. Half-siblings should be added later.

Older brother

Older sister

You Younger brother

A horizontal line connecting brothers and sisters is called a sibship line

A vertical line leading to a person’s symbol is called an individual line

Jane Jones b. 4/25/1990

asthma

Parents

Draw your parents above yourselfDraw a horizontal line connecting your parents. Then draw a vertical line from the horizontal line to your symbol (if only child) or the sibship line. The horizontal line is a relationship line. If your biological parents are divorced or not together, draw a diagonal line through the horizontal line. If either of your parents have children with a different partner, draw a second relationship line to the other partner. Any half-siblings from this relationship should have a vertical line stemming from the new relationship line.

You You Half-brother

A vertical line leading from parents to offspring is called a line of descent

Jane Jones b. 4/25/1990

asthma

Aunts, Uncles, Cousins, Nieces & Nephews

Your parents’ siblings (your aunts and uncles) are drawn next to them and connected with a sibship line. It’s okay if you have to draw them out of order by age, but do your best!In order to save space, you may choose not to include the spouses of your parents’ brothers and sisters. When drawing cousins, connect their line of descent directly to their parent or to their parents’ relationship line. Same concept when drawing the children of your siblings (nieces and nephews).

You Cousin Cousin Cousin

Uncle Aunt Aunt’s husband

Jane Jones b. 4/25/1990

asthma

Grandparents

Draw your maternal grandparents above your mother, or your mother’s sibship line. Connect them with a relationship line (if applicable) and draw a line of descent to your mother or mother’s sibship lineDraw your paternal grandparents above your father, or your father’s sibshipline. Connect them with a relationship line (if applicable) and draw a line of descent to your father or father’s sibship line

You

Maternal grandparentsPaternal grandparents

Jane Jones b. 4/25/1990

asthma

Step 3: Put it all together and what do you get . . .

Henry Black b. 7/17/40

high blood pressure

Diane Black b. 4/10/40

d. 2/10/2000, breast cancer

Cory Green b. 11/9/62

Susan Green b. 7/6/67

Sara Black b. 12/6/63

Mark White b. 7/1/66

Jack Smith Sr. b. 8/3/83

Jackie Smith b. 2/12/85

Jane Jones b. 4/25/1990

asthma

Justin Smith, Jr. b. 1/1/2008

Carl Green b. 4/27/2001

Carrie Green b. 9/19/99

cystic fibrosis

Jill Jones b. 9/4/94

Sean Black b. 8/9/89

Sam Black b. 9/1/91 born with

heart defect, repaired at

birth

Megan White b. 6/9/96

Mary White b. 8/1/66

diabetes II

Steve Black b. 5/5/62

Judy Jones b. 6/5/65

breast cancer at age 41

John Jones b. 2/6/62

high cholesterol

Dorothy Jones b. 10/15/43

Jeffrey Jones b. 12/11/42

heart attack at 64

What to Do with Your Pedigree

Take it home! Clean it up, add to it, ask your parents about corrections – have a complete and accurate pedigree on handStore your pedigree in a safe place. Every couple of years, take it out and update it as necessary.Give a copy to your physician. It might come in handy to have this information in your medical chart someday in the future.If there is something on your pedigree which concerns you, take it to a medical professional or genetic specialist for their assessment.

Discussion

Why would a pedigree be useful to a doctor or genetic counselor?What can be determined from looking at our example pedigree? If you were a doctor or genetic counselor, what would you discuss with our example family?Should all doctors be required to ask their patients about their family health history? Why or why not?